Device for the cooling of compressors with pistons



A. HUGUENIN Feb. 21, 1933.

DEVICE FOR THE COOLING OF COMPRESSRS WITH PISTONS 5 Sheets-Shearl 1 Filed Sept. 14,. 1926 E .ZZ

, .suction ra/ve 7 re valut/'0n 7 suction rein/et of' coo/edges Feb. 21,1933. A. HUGUENIN DEVICE FOR THE COOLING 'OF` COMPRESSORS WITH 'PISTONS Filed sept. 14, 192e 3 sheets-snee; -2

A. HUGUENIN 1,898,729

DEVICE FOR THE COOLING OF COMPRESSORS WITH PXSTONS` Feb. 21, 1933.

5 Sheets-Sheet 5 Filed Sept. 14, 1926 Patented Feb. 2l, 1.933

Unirse STAT-ssj emes.

. ALBERJD HUGUENIN, or Pears,- FRANCE nevica For. THE comme or eonenssonswien erstens.

Application inedV septmer' 14, 1926', serial No. 135,460; ane-1in France November 6, i925.

The cooling means for compressing engines or machines with pistons are to-day divided into two distinct kinds:

lst- A jacketing of the cylinders.

2nd- Intermediate coolers between-fthe different levels or stages inthe case of compressing machines with several stages.v Inthe case of a. one-stage compressing machine, an after cooler is provided or not at the outlet of the single stage, according to the use to which the compressed gas is to be adapted.

vAccording to the present invention a box is provided on the cylinderwith compression piston, two pipes connect said box respectively with the inlet and the oulet of a cooler and means are provided to open the communication of the box with the outlet of the cooler at the end of the exhaust stroke and during the admission stroke, and to produce, at thev endv of a certain time after the begin"- ning of the admission stroke, the closing of an exhaust valve adapted-cto connect the cylinder withg the box. Use can' be made-of a cylindrical slide-valve' sliding in a cylindrical box and of. exciting means sending exciting currents in electro-magnetic devices enclosed within said box so as to move the slide valve at the end of every piston stroke and to open the exhaust valve during the last part of the exhaust stroke andthe first partei the admission stroke.

vThe present invention proceeds yin an entirely different manner for the cylinder cooling. This process will be described with reference toV the accompanying drawings given by way of example.

Fig. l shows a `pressure-volume .diagram drawn, for instance, for a three-stage com# presser, and,

Fig.- 2 shows the entropie diagram oi the cycle of one stage.

Fig. 3 is a diagram of a compressor operating according to the new process.

Fig. 3a is a detailed section of a -suction valve.

Fig.- 4 is a diagrammatic elevation showing endwise the dri-ving mechanism which is situ'- ated on the right at the bottom of Fig. 3.

Fig. 5 is' a diagram of a mechanism `provided with eccentrics.

Fig. 6 shows four different positionsof aneccentric and a lever. Fig. '7 indicates different curves described' by one point of the lever. l F'fg; 8 is vertical section showing some detailsl'oi ai valve and valve.k i ,y Y y Figs. V8a and 8b are longitudinal and cross sections of the insulators through the cover.'

Fig; 9y is a horizontal section made according to the' broken line 9-9 of- Fig. 8. v Figs. 10, 11 and 12 are diagrams showing the representative curves of the slide-valve motions, of the exhaust valve and/of the suc-- tion valveA of one of the cylinders of thecompressor, the ordinates being proportional to the vertical displacementsv of these parts and the abscissas being proportional to the' times. TheY parts of the diagram. vvdrawn in fullv lines in Fig. 1 show thenormal cycles of the of'a deli-very Vslidethree stages'of'the compressor, taking into account an intensive intermediate cooling, as it is normally used nowadays, rio-supplementary explanation appearing' as being' necessary relatively kto the same. p

The part of said diagram which is covered j with hatch-ings in fullv lines shows the `ex pansion work' supplied from the' gases retained Vin the clearance spaces of the different cylinders, which work is, by the way, com` pletely'flost to-day because the imperfect expansion does not succeed in reaching the full temperature fall of the gases at the adn'iis` l sionlevel. Tothe three stages l, 2 3 are adY` j oinedthe intermediate coolersLrII, and the aftercooler III which are' diagrammatically shown in theformy of coils; the normal circuit of the gases is indicated in iull V line betweeny the different stages 1 2, 2 3 and at the out-y let of the stage' Y Accordingto'th'e present invention, there will be admitted atthe dead pointV ofy the stroke of the piston. corresponding to thefull expelling or exhaust a small partv of they gases which have passedthrough the intermediate cooler; the How of these gases in the `ey'liri ders is indicated `for vthe threel stages 1,2, 3 by .dotted arrows 1a, 2a, 3a,y i. e. they enter the cylinders'atthe-dead point-of the stroke at ythe exhaust pressure but-cooled. ,"lhisi amount of gas normally cooled by the intermediate aftercoolers at the temperature of suction of the first stage, mixing itself with the compressed gas inthe clearance space, noticeably increases the volume thereof while raising the temperature of same but to a small extent. This injected gas expands in the cylinders and its external work is represented by the part covered by hatchings in broken lines, due to the noticeable reduction 0f temperature during its expansiongitalso allows the gas compressed in the clearance space and mixed with the injected gases to supply allofthe useful expansionwork and the surface covered with hatchings in full lines becomes also useful in this case.

The result thereof is of course a decrease of the useful volume of the cylinder capacity and Figure l indicates the proportion which will likely be adopted in practice and which will amount to about 0.7, while it amounts to about 0.9 up to now.

.The temperaturey in thel cylinder, during suction, is, due to this fact, sensibly lower than that which corresponds tothe outflow from the intermediate cooler and the volume of ,the cylinder contents or capacity will therefore be better utilized as, for a constant absolute volume, a decrease of specific volume corresponds to an increase. in the weight of the admitted gas.

EThis newV system of cooling therefore simply requires the addition of aninjection valve which will bel controlled from another source and .thevariable stroke of which will easily allow of varying at will the degrees of cooling The cylinder is a simple one,-,heat-insulated from outsideso as to allowunder the best possible conditions the complete expansion of the cooled injected gas and of the gas which remains in the clearance space.

Jersvthepactual volume of the cylinder is used, with the new system, only to about 0.7 instead of 0.9 as statedv above, its diameter has to be chosen a' triiie bigger'. .Anyhow its outside diameter, as'it isnow only a single cylinder, will be less than theoutside diamete'r of. the up-to-now standard waterjacketed cylinder.

Theinlet valve for the cooled gases being under control, it is still very easy to use one or sev-eral short injections of cooled gases during the compression, this representing still a cooling which is much more efficient than the one of the jacketing of the cylinder which has been heretofore universally used;

The entropy diagram of yF igure 2 can be briefly explained as follows v Y In the ordinary cycle of'one stage of a compressor or compressing machine with piston, the suction is eected at the pressure p and the temperature to, specific volume co. The adiabatic compression, i. e. withy constant entropy, as far as the pressure 01 takes place according to the vertical line drawn in dash and dotted lines and nally comes theoretically to a temperature t1 and a specific volume v1, the intermediate cooling which follows this stage will theoretically return to the same pressure p1 the specific volume from c1, to vL1 and the gas will be admitted at this specic volume to the followingstage of the 5 compressing machine.

dead point at the end ofthe exhaust stroke,

the volume compressedv to t1, u1 at the pressure p1 will have added thereto a volume injected at the temperature to and at the specific volume ci, thereby producing a mixture which will aways be at the pressure p1, at the temperature t3 and the specific volume @3. In virtue of the precautions which are taken, the-adiabatic expansion can effectively take place and the pressure p0 will be attained at the temperature t4 and the specific volume '05. The admission of gas during. the suction taking place at the temperature to, before the beginning of the compression, the temperature t5 and the specific volume c6 will be attained, so that the adiabatic compression will take place according to the full lines of the diagram and reach p1 at the temperature t2 and at the speciiicvolume v2.

The usual cycle is represented in mixed lines at the places where it does not confound itself with the new cycle,

which is represented in full lines. 7^

The surface which is hatched inclined to the right above the absolute temperature 0,

represents in calories the work of compres sion to be furnished in accordance with standard practice, a -very small part of same A having to be deducted for the very small useful work produced by the expansion of the gas contained in the clearance.

The surface hatched vertically represents in the same way the work of compression to be furnished in accordance with our invention, but a'marked portion of the surface hatched inclined to the left has to be'vdeducted representing the useful work of expansion, of course of a much smaller weight of gas, as the weight of the actually compressed gas.

The decrease is visibly an important one and, taking intol account the freduction of Vefficient volume of the cylinder capacity or contents, in the V above indicated proportions, there still remains, always to the benefit of the cycle according to the present invention,

.valve giving access to the cylinder. change of communication with the hot gas proves the outputs which have been `up tok now obtained, while securing the great simc p'li-fications which are above mentioned.

The injection valve can be of anytype and vis forV example constituted, for theV firstV stages, by a balanced valve and Vfor the last stages by a needle-valve.

In the form of construction of compressing machine according to the invention.

which will be described by way of example,

it has been supposed that referred to a two` stage compressing machine,

every stage bein'gdouble acting one.

t is of advantage, to all points of view,

to reduce, as regards piston compressors provided with the new system of cooling by injection or back-expansion ofgcooled gases, the clearance space as much as possible; it is furthermore necessary to reduceto the strict minimum the number'of the pieces for the control and of the channels or conduits leading to the ports'of the cylinders, as these are precisely the cavities which produce the largest part oi the clearance which, anyhow, cannot Vbe practically reduced to zero. The more the number of ports giving directly access to the interior of the cylinder isl reduced, the more the leaks which are unavoidable andV inherent to every design will be reduced; therefore it is of a great advantage not to increase in any case the numberof valves of any system for the use of the back-expansion.

It is very important to give to the exhaust valve a stroke which is as large as possible and considerably greater than the stroke of the automatic spring valves as most generally used at present; it is furthermore possible to combine the exhaust valve with the valve for the inlet of cooled gas, thus having only one The and cold gas channels can take place behind the exhaust valve, and this combination being quite new, affords the great advantage to reduce in very noticeable proportions the clear-y ance as compared with the actual standard design. y

The compressorshown in Fig. 3 comprises two cylinders a and b, each of them being double acting, with the inlet valves c and Z Vprovided in the cylinder heads and of the automatic type ordinarily in use for the cylinder a; and e, and f for the cylinder b; Fig. 3a shows the essential particularsof the suction valve c and c1 indicates the seat c2 which is connected by means of the stud c3 with plateguard and the nut a, in the standard wayto the seat c1. The exhaust valves are g and h for the cylinder a and are provided in Vthe cylinder heads, and' z' and Zo arrangedin a similar manner for the cylinder Z); every case 'or box forthe exhaust valve is provided with a cylindrical slide valve which is represented at Z and m for the valves g and ZL of the cylinder a, and at a and o for the valves z' andt Zr: of the cylinder Z); p is the suction pipe lead- 1 ing to the suction valves of the first stage,

and gV the exhaust pipe of this stage leading into the intermediate cooler i', into which the cooling water enters Vthrough the pipe ys to leave the same through the pipe t.

A; pipe u returns part of the gases cooled' by Vthe intermediate cooler to the valve-boxes g and Zz) and the cylindrical slide-valves Z and m connect these valve boxes either with the exhaust pipe Q or with the return pipe for the cooled gases u; o denotes the exhaust pipe or conduit of the second stageA leading the gases to the ai'itercooler w into which the cooling` water enters through the pipe 0c to leave the vsame through the pipe y. The pipe or conduit a finally 'returns part of the cooled gases having passed through the aftercooler to the valve-boxes z' and ZJ and the cylindrical vslide-'valves n and 0 connect the boxes of these valves either with the pipe o for the hot gases or with the pipe a for the cooled gases.

The exhaust valve g and the cylindrical slide-valve Z will now be specially described with reference to Figs. 8 and 9 in which these parts are represented as being moved by an i electromagnetic device; the expelling or ex- CZ is interposed between the same and another sleeve e; also of anti-magnetic metal which Y ,Y

is ended by a piston f; the whole valve orming but a single piece has its weight balanced by a spring g; (this spring is under tension for the valves g and i provided in the upper heads of the cylinders and under compression for the similar valves )tand Zr: provided in the lower heads oi' the cylinders). The valve rod moves in a stationary cylinder la made also of anti-magnetic metal forming in its upper part ak cylinder c in which the piston f moves; the cylinder and the piston are designed in a. known manner so as to act as dash-pots at both ends Aof the vautomatically form dash-pots at the end of the stroke.

Two coils p and g concentric with the axis of the valve can act upon the magnetic circuit 7" moreover completed by the soft iron core cl forming one part with the` the covers through insulators ai and y.

Figs. 8a and 8b being a cross section according to A-Aof Fig. 8a represent one of these insulators. Each carries four wires V1 which are embodied in insulating material V2. A metallic sleeve V3 in two pieces is held on by a conical one-piece sleeve V4 also made of steel. rllhe whole is secured into the insulating cylinder V5 by means'of the nut V6, the cylinder itself being fixed in vthe casing by the nut 'V7 pressing on the tightening ring VS and secured itself by the additional nut V 9. Finally the dotted position e shows the valve as being lifted from its seat and the passage with a very large cross section afforded to the gas entering and leaving the linder; the inlets and outlets of the pipes u and g are aso indicated in Fig. S and the flow marked by corresponding arrows.

By exciting either the one or the other of the coils 79 or and s or t', the valve g and the slide-valve l will be either at the bottom, or the top end of the stroke; it is easy to understand that by reasonable choice of the working data, it is possible to impart to the two valves a relatively large stroke with a very small consumption of power whereas their weight is completely balanced and their inertia is very small. Through the periodic excitation either of the lower or of the upper coils, very quick motions both of the exhaust valve g and of the cylindrical slide-valve Z will be obtained. Fig. 8 shows the two closing devices in the lower position, the valve g closing the interior of the cylinder and the cylindrical slide-valve Z giving access to the cold gases, through the pipe a, to the valve box.

Fig. l0 shows for two revolutions of the crank-shaft the motions of the cylindrical slide-valve which takes place at the dead points. The hot 0ases have access tothe box of the valve g during all the exhaust stroke. At the dead point of the suction stroke, the slide-valve effects the downward stroke and allows, for all this stroke, cold gases to have access to the box of the exhaust valve; at the next dead point between the suction and exhaust stroke, this slice-valve is lifted and again gives access tov the hot gases.

Fig. 11 shows the motion of the exhaust valve a in a similar manner in function of thetime and for. the same two full revolutions of the crank shaft, its up and down strokes; the ascending stroke during the exhaust stroke of the piston corresponds to the point at which the pressure of operation is attained in the cylinder, the same being followed .by the period of exhaust of the hot gases in to the intermediate cooler; the closing of the valvesometime after the dead point of the beginning Vof the suction stroke stops the reintroduction of the cold gases at the same pressure into the cylinder, in order to start the useful expansion forwork and for cooling of the gases then contained in the cylinder.

To complete the showing of the motions f the valve, Fig. 12 gives the opening of the suction valve c, CZ, e or f, and the duration of'its automatic opening during the suction strokeafter the gases effecting the back-ex pansion will have expanded at the suction pressure, and its closing at the dead point between the suction and exhaust stroke.

The mechanism, such as it is represented,

therefore allows to carry out in a very simple manner the principle of the back-expansion according to the invention with a minimum of shutting olf devices giving access to the interior of the cylinder as the usual. automatic exhaust valve with a very small stroke and consequently a very large diameter, or even an annular one with several rings, is replaced here by a single valve with a big stroke, acting at the same time as a valve for the reintroduction of the cold gases at the beginning of the suction stroke of the piston. The speed of the movements of the exhaust valve for back-expansion, on the one hand, and of the cylindrical slide-valve, on the otherhand, ishigher, than with any other either mechanical or hydraulic drive. Finally this drive through electromagnets allows to provide for a. complete closing of the exhaust valve box and therefore prevents in an absolute manner every loss of gases, which would not be the case with a mechanical or hydraulic drive of the said valve the former cally exciting coils of the electromagnets.'

By means of spur gear wheels, D, E and F, the two driving shafts G and H parallel to the crankshaft lAsmove in a reverse direction the one to the other; the shaft G moves clockwise and the shaft H moves counter clockwise for an observer placed at the ,end of the com ressor on the side of this drive. The shaft carries an eccentric I which is Leasing shown diagrammatically in Fig. 5 and in a substantial arrangement in Fig. 6; this eccentric is connected with a rod K the left while its right end M describes a curve in the direction of the arrow X1. Fig. 6 shows four main positions of the eccentric I and the parts of the curve N described by its end M.

The shaft H carries in a similar manner eccentric O which causes a curve P to be described in the direction of the arrow X2 by the end Q of the eccentric rod O the right end R of which moves in a guide S. The two ends M and Q of the eccentrics I and O act upon a switch or interrupter with 3 mercury Contact electrodes in the empty space represented at T and at the upper part ofthe curves N and P, the endsl M and Q cause the said switch T to rock in the one or in the other direction. In one position, it closes the circuit on one oi the-coils oi' the electromagnetand in the other position the other magnet for the s ame member to be operated.I

Under the action of the screws U and V, the slides S can7 as shown in Fig. 7, assume different positions thereby raising or lowering in space the curves described by the ends M and Q of the eccentric rods this enabling to easily control the moments of energizing and Cle-energizing of every coil provided in the exhaust valve box.

This mechanism therefore allows to regulate at will the play or' motion of the exhaust valves for the back-expansion, on the one hand, and of the cylindricalV slide-valve, on the other hand.

It is moreover easy to adjust the same while the compressor is in operation and this adjustment can moreover be automatically made dependent upon the exhaust pressure at the last stage of the compressor, in order to control the cooling of the cylinders even when working under conditions of disturbance so as to maintain, if desired, as perfect as possible permanent balance of the work of the different stages of the compressor adapted to operate under exhaust pressures capable of varying in large proportions.

In order to reduce the eect of retardation of the energy of the switching in and cutting ont currents in the electric circuits, the energy of these currents will be absorbed, as usually done, by resistancesconnected in series, or by combinations oi resistances and of capacities.

It will be understood that the drawing only shows by way of example the principle which consists in combining the exhaust valve with the valve for the reintroduction of the cold gases and with the device for reversing the communications of the hot gases and the cold gases with the box of the said valve; the intrinsic advantages of the drive by electromagnets have moreover been exposed in this description, but the delivery or distributing parts canA alsofbe operatedby mechanical' o r hydraulic driving devices ,and

-even also by Votliers'ystenis of electric drive. end of which moves 1n a slideway or guide .Having thus,V described .my.,process and apparatus, vwhat I claim as `new therein, and

my owninvention, is :i-

an exhaust valve connecting the 'cylinder-i with the said `box anda valve provided for alternatively closing one of the two mentioned pipes, means for controlling the last two valves and adapted to open the communication ofthe said chamber with the outlet lof the cooler at the end of the exhaust stroke during the admission stroke, and at its end the closingofthe exhaust valve.

2. In a piston compressor with; intermediate and after-cooler, the combination of a-- cylinder with compressing piston, acooler, a cylindrical box on said cylinderv and two pipes connecting this box, the one with the inlet of the said cooler, and the other with the the yadmission of ythe gas to be compressed into 4the cylinder, an exhaust valve between the cylinder and the said box, a cylindrical slide-valve sliding in this box, electromagnetic devices enclosed within the said box forA controlling or driving the exhaust valve and the slide valve, exciting means for the purpose of sending exciting currents into'the 1. In a piston compressor with tinter-medioutlet of the same cooler, an inlet valve for f said driving devices, the said exciting means being so connected as to remove the slidevalve at the endof every piston stroke `and to open the exhaust valve during the last part vio of the expelling stroke and the first part of Y the admission stro-ke.

3. In a piston compressor, a cylinder provided Lwith an after-cooler, a box on said cylinder, a discharge valve connecting the cylinder with the box, separate means-connectilo ing the box with the inlet and the' outlet of the intermediate and after-cooler, and a slide valve alternately opening and closing said separate means.

4. In a piston compressor, a'cylin'der provided with an after-cooler, a box o-n said cylinder, a discharge valve connecting the-cylseparate means and electromagnetic meansl for controlling the slide-valve andthe discharge valve.

5. In a piston compressor, a cylinder pro- A Vvided with an after-coolena box on said cylinder,` a discharge valve connecting the Acyll?? indei' with the box, separate means connecting the box with the inlet and the outlet of the intermediate and after-cooler, and a slide valve alternately opening andclosing said separate means, and electromagnetic means for controlling the slide valve and the discharge valve, a Contact device controlling said electromagnetic means, and means for adjusting said electromagnetic means.

Intestimony whereof I have hereunto affixed my signature. Y

ALBERT HUGUENIN.

leo 

